Breeding method for tetraploid Ricinus communis

Abstract

The present invention provides a breeding method for tetraploid ricinus communis. The method comprises: collecting a ricinus communis germplasm resource, performing morphologic character analysis and chromosome ploidy identification, selecting good diploid varieties, carrying out mutagenesis by using colchicine and oryzalin; performing chromosome ploidy identification on F1 generation seeds, selecting homozygous tetraploids, and performing economic character analysis and identification on the F2 generation, so as to breed good tetraploid ricinus communis.

The invention claimed is: 
     
       1. A breeding method for tetraploid  Ricinus communis  L., comprising the following steps:
 providing diploid  Ricinus communis  L. seeds, 
 subjecting the naked embryos of the  Ricinus communis  L. seeds obtained after artificial removal of endosperms to a forced absorption method with mixed mutagens to perform a doubling process for tetraploidization, 
 subjecting the newborn F1 young leaves to chromosome analysis and ploidy identification, 
 removing chimeras and aneuploids, and 
 screening for homozygous tetraploid plants, which are then subjected to large-scale planting and cultivation management according to conventional methods for cultivating  Ricinus communis  L. 
 
     
     
       2. The breeding method for tetraploid  Ricinus communis  L. according to  claim 1 , wherein the mixed mutagens are a mixed solution of colchicine and oryzalin. 
     
     
       3. The breeding method for tetraploid  Ricinus communis  L. according to  claim 1 , wherein the basic number of the  Ricinus communis  L. chromosome is x=10, and the diploid chromosome number of somatic cells is 2n=2x=20. 
     
     
       4. A breeding method for tetraploid  Ricinus communis  L., comprising the following steps:
 1) providing diploid  Ricinus communis  L. seeds; 
 2) subjecting the  Ricinus communis  L. seeds to sterile disinfection using conventional disinfection methods, then removing the endosperms, stripping the seed embryos out, placing the seed embryos into 1/2MS medium, and incubating the seed embryos at 23° C.±2° C. without lighting until the seed embryos have germinated; 
 3) transferring into an aqueous solution containing mixed mutagens of colchicine and oryzalin at a certain mass concentration, to perform a doubling process in darkness at a lower temperature of 15-20° C. for 48-72 hours; 
 4) transferring into 1/2MS medium, to continue to cultivate at 23° C.±2° C. with a lighting of 1000 Lux, 16 hours/day; 
 5) transplanting the seedlings in bottles into disinfected soil when the seedlings have developed into 4 true leaf stage and their roots have a length of 3-5 cm; at 3 days before transplanting, opening the caps of bottles for acclimatization; the transplanted seedlings must be carefully managed; 
 6) subjecting the newborn young leaves of F1 seed embryo to chromosome analysis and ploidy identification, removing chimeras and aneuploids, screening for homozygous tetraploid plants; and 
 7) subjecting the  Ricinus communis  L. tetraploids to large-scale planting and cultivation management according to conventional methods for cultivating  Ricinus communis  L., subjecting the F1 seeds of tetraploid  Ricinus communis  L. to chromosome analysis and ploidy identification again, removing chimeras and aneuploids, screening for a new homozygous tetraploid  Ricinus communis  L. germplasm. 
 
     
     
       5. The breeding method for tetraploid  Ricinus communis  L. according to  claim 4 , wherein the conventional disinfection method is as follows: disinfecting with 75% alcohol for 60 seconds, rinsing with sterile water, and then disinfecting with 2% sodium hypochlorite for 15 minutes, rinsing with sterile water for 3 times. 
     
     
       6. The breeding method for tetraploid  Ricinus communis  L. according to  claim 4 , wherein the mass percent concentrations of the colchicine and oryzalin solutions are 0.02%, respectively; and the final concentration of each of the mixed mutagens is 0.01%. 
     
     
       7. The breeding method for tetraploid  Ricinus communis  L. according to  claim 4 , wherein the conditions for the management of transplanted seedlings are as follows: maintaining the temperature at 25° C.±2° C., the humidity at 65%±5; the soil condition is normal sandy loams. 
     
     
       8. The breeding method for tetraploid  Ricinus communis  L. according to  claim 4 , wherein the steps of chromosome analysis and ploidy identification are as follows: harvesting newborn young leaves at 8-9 a.m., pre-processing with 0.002M 8-hydroxyquinoline for 3-4 hours, then preparing chromosome specimens of  Ricinus communis  L. through a wall degradation hypotonic method utilized in the preparation of chromosome specimens of plants, removing chimeric and aneuploid plants, screening for plants whose somatic cell chromosome is 2n=4x=40 to obtain homozygous tetraploid plants.